1. Field of the Invention
The invention is in the field of cleaners for hard surfaces and relates to wet wipes which are impregnated with a special species of a nonionic surfactant.
2. Prior Art
For the cleaning of hard surfaces, liquids of greater or lesser viscosity are usually used, which are applied directly, run off from the surface to be cleaned and in so doing carry along the majority of the soiling. Another application form which is enjoying increased importance are wet wipes, which are textile fabrics or else tissue papers which are impregnated with a cleaning liquid. Thus, for example, international patent application WO 95/35411 (Procter and Gamble) proposes wet wipes albeit predominantly for cosmetic applications, which comprise, in addition to mineral oil, fatty acid esters, fatty alcohol ethoxylates and fatty alcohols.
The disadvantage of the use of these wet wipes is that the surfactants used leave behind a residue in the form of smearing, which makes the treated surface less shiny or even makes it appear soiled. A further problem arises in the production of the wet wipes. In order to impregnate the fabric or tissue paper with the cleaning solution, it is either sprayed therewith or immersed therein where, in both cases, it is possible for the output in production to be reduced as a result of foam formation or insufficient wetting. A first object of the present invention was therefore to provide wet wipes using special surfactants which are free from the problems described above.
For logistical reasons, the use of concentrates for the preparation of impregnation solutions for the wet wipes is advantageous. It is disadvantageous that the concentrates often show a tendency toward foam formation upon dilution. Furthermore, gel phases may form, which leads to increased time expenditure in the preparation of the impregnation solutions. In both cases, the production output is reduced. A further object of the invention was therefore to provide surfactants with which concentrates can be prepared which, by virtue of their viscosity, storage stability, lack of foam upon dilution and rapid dilutability, permits a technically simple and therefore cost-effective production of the wet wipes.
The invention provides wet wipes which are characterized in that they are impregnated with mixed ethers.
Surprisingly, it has been found that nonionic surfactants of the mixed ether type, preferably in combination with alkyl oligoglucosides, satisfy the complex object in an excellent manner. Impregnating agents based on mixed ethers have proven in the application to be low-viscosity and virtually foam-free, and in application the wet wipes impregnated therewith do not leave behind any streaks and do not impair the shine. Concentrates based on mixed ethers are low-viscosity and, upon dilution to the application concentration, particularly low-foaming.
Mixed Ethers
Mixed ethers are known nonionic surfactants which are usually obtained by adding ethylene oxide and/or propylene oxide, blockwise or in random distribution, onto suitable primary alcohols, and then etherifying the alkoxylates with alkyl halides; the etherification is also referred to as xe2x80x9cterminal cappingxe2x80x9d. The mixed ethers usually conform to the formula (I) 
in which R1 is an alkyl and/or alkenyl radical having 1 to 22, preferably 6 to 18 and in particular 12 to 16, carbon atoms, R2 is an alkyl radical having 1 to 12, preferably 4 to 8, carbon atoms or a benzyl radical, x and z, independently of one another, are 0 or numbers from 1 to 40 and y is 0 or numbers from 1 to 10, with the proviso that the sum of the carbon atoms in the radicals R1 and R2 is at least 4, preferably at least 8 and in particular at least 12, and the sum of the indices x, y and z is different from 0. Typical examples are the etherification products of the addition products of, on average, 1 to 40, preferably 5 to 30 and in particular 8 to 15, mol of ethylene oxide and/or 1 to 10, preferably 2 to 5, mol of propylene oxide onto caproic alcohol, caprylic alcohol, 2-ethylhexyl alcohol, capric alcohol, lauryl alcohol, isotridecyl alcohol, myristyl alcohol, cetyl alcohol, palmoleyl alcohol, stearyl alcohol, isostearyl alcohol, oleyl alcohol, elaidyl alcohol, petroselinyl alcohol, linolyl alcohol, linolenyl alcohol, elaeostearyl alcohol, arachyl alcohol, gadoleyl alcohol, behenyl alcohol, erucyl alcohol and brassidyl alcohol, and technical-grade mixtures thereof with methyl chloride, butyl chloride, benzyl chloride or octyl chloride. The amount of mixed ethers used can, based on the wet wipes, be 0.05 to 2% by weight and preferably 0.1 to 0.5% by weight and, based on the concentrates, 10 to 50% by weight, preferably 15 to 25% by weight.
Cosurfactants
In a preferred embodiment of the present invention, the mixed ethers are used together with further anionic, nonionic, cationic and/or amphoteric or zwitterionic surfactants.
Typical examples of anionic surfactants are soaps, alkylbenzenesulfonates, alkanesulfonates, olefin-sulfonates, alkyl ether sulfonates, glycerol ether sulfonates, xcex1-methyl ester sulfonates, sulfo fatty acids, alkyl sulfates, fatty alcohol ether sulfates, glycerol ether sulfates, hydroxy mixed ether sulfates, monoglyceride (ether) sulfates, fatty acid amide (ether) sulfates, mono- and dialkyl sulfosuccinates, mono- and dialkyl sulfosuccinamates, sulfotriglycerides, amide soaps, ether carboxylic acids and salts thereof, fatty acid isethionates, fatty acid sarcosinates, fatty acid taurides, N-acylamino acids, such as, for example, acyl lactylates, acyl tartrates, acyl glutamates and acyl aspartates, alkyl oligoglucoside sulfates, protein fatty acid condensates (in particular wheat-based vegetable products) and alkyl (ether) phosphates. If the anionic surfactants contain polyglycol ether chains, these may have a conventional homolog distribution, but preferably have a narrowed homolog distribution.
Typical examples of nonionic surfactants are fatty alcohol polyglycol ethers, alkylphenol polyglycol ethers, fatty acid polyglycol esters, fatty acid amide polyglycol ethers, fatty amine polyglycol ethers, alkoxylated triglycerides, hydroxy mixed ethers, unoxidized or partially oxidized alk(en)yl oligoglycosides or glucuronic acid derivatives, fatty acid N-alkylglucamides, protein hydrolysates (in particular wheat-based vegetable products), polyol fatty acid esters, sugar esters, sorbitan esters, polysorbates and amine oxides. If the nonionic surfactants contain polyglycol ether chains, these may have a conventional homolog distribution, but preferably have a narrowed homolog distribution.
Typical examples of cationic surfactants are quaternary ammonium compounds such as, for example, dimethyl distearyl ammonium chloride, and ester quats, in particular quaternized fatty acid trialkanolamine ester salts. Typical examples of amphoteric or zwittionic surfactants are alkylbetaines, alkylamidobetaines, aminopropionates, aminoglycinates, imidazolinium-betaines and sulfobetaines. Said surfactants are exclusively known compounds. With regard to structure and preparation of these substances, reference may be made to relevant review works, for example J. Falbe (ed.), xe2x80x9cSurfactants in Consumer Productsxe2x80x9d, Springer Verlag, Berlin, 1987, pp. 54-124 or J. Falbe (ed.), xe2x80x9cKatalysatoren, Tenside und Mineralxc3x6ladditivexe2x80x9d, Thieme Verlag, Stuttgart, 1978, pp. 123-217.
Typical examples of particularly suitable surfactants are fatty alcohol polyglycol ether sulfates, monoglyceride sulfates, mono- and/or dialkyl sulfosuccinates, fatty acid isethionates, fatty acid sarcosinates, fatty acid taurides, fatty acid glutamates, xcex1-olefinsulfonates, ether carboxylic acids, fatty acid glucamides, alkylamidobetaines, amphoacetals and/or protein fatty acid condensates, the latter preferably based on wheat proteins.
Alkyl and/or Alkenyl Oligoglycosides
Performance investigations demonstrate that mixtures of mixed ethers and alkyl and/or alkenyl oligoglycosides are particularly advantageous. The latter are known nonionic surfactants which conform to the formula (II),
R3Oxe2x80x94[G]pxe2x80x83xe2x80x83(II) 
in which R3 is an alkyl and/or alkenyl radical having 4 to 22 carbon atoms, G is a sugar radical having 5 or 6 carbon atoms and p is a number from 1 to 10. They can be obtained by the relevant processes of preparative organic chemistry. By way of representation for the extensive literature, reference may be made here to the specifications EP-A1 0301298 and WO 90/03977.
The alkyl and/or alkenyl oligoglycosides can be derived from aldoses or ketoses having 5 or 6 carbon atoms, preferably from glucose. The preferred alkyl and/or alkenyl oligoglycosides are thus alkyl and/or alkenyl oligoglucosides. The index number p in the general formula (II) gives the degree of oligomerization (DP), i.e. the distribution of mono- and oligoglycosides, and is a number between 1 and 10. While p in a given compound must always be an integer and can here primarily assume the values p=1 to 6, the value p for a certain alkyl oligoglycoside is an analytically determined calculated parameter which in most cases is a fraction. Preference is given to using alkyl and/or alkenyl oligoglycosides with an average degree of oligomerization p of from 1.1 to 3.0. From a performance viewpoint, preference is given to those alkyl and/or alkenyl oligoglycosides whose degree of oligomerization is less than 1.7 and is in particular between 1.2 and 1.4.
The alkyl or alkenyl radical R3 can be derived from primary alcohols having 4 to 11, preferably 8 to 10, carbon atoms. Typical examples are butanol, caproic alcohol, caprylic alcohol, capric alcohol and undecyl alcohol, and technical-grade mixtures thereof, as are obtained, for example, in the hydrogenation of technical-grade fatty acid methyl esters or in the course of the hydrogenation of aldehydes from the Roelen oxo synthesis. Preference is given to alkyl oligoglucosides of chain length C8-C10 (DP=1 to 3) which are produced as for runnings during the distillative separation of technical-grade C8-C18-coconut fatty alcohol and may be contaminated with a content of less than 6% by weight of C12-alcohol, and also alkyl oligoglucosides based on technical-grade C9/11-oxo alcohols (DP=1 to 3). The alkyl or alkenyl radical R3 can also be derived from primary alcohols having 12 to 22, preferably 12 to 14, carbon atoms. Typical examples are lauryl alcohol, myristyl alcohol, cetyl alcohol, palmoleyl alcohol, stearyl alcohol, isostearyl alcohol, oleyl alcohol, elaidyl alcohol, petroselinyl alcohol, arachyl alcohol, gadoleyl alcohol, behenyl alcohol, erucyl alcohol, brassidyl alcohol, and technical-grade mixtures thereof, which can be obtained as described above. Preference is given to alkyl oligoglucosides based on hydrogenated C12/14-coconut alcohol with a DP of from 1 to 3. The alkyl and/or alkenyl oligoglycosides can, based on the wet wipes, be used in amounts of 0.05 to 2% by weight and preferably 0.5 to 1% by weight and, based on the concentrates, in amounts of from 10 to 50% by weight, preferably 25 to 25% by weight, where the weight ratio of mixed ethers to glycoside may be in the range from 10:90 to 90:10, preferably 25:75 to 75:25 and in particular 40:60 to 60:40.
Tissue Papers and Tissue Fabrics for Moistened Papers
Tissue papers to which the present invention refers can be single-ply or multi-ply. The papers generally have a weight per square meter of from 10 to 65 g, preferably 15 to 30 g, and a density of 0.6 g/cm3 and below. Examples of tissue papers to which the invention may extend are, in addition to household wipes, naturally also toilet papers, pocket tissues, face-cleansing wipes, make-up removal wipes, refreshing wipes and the like. In addition to the paper-based tissues, corresponding tissue fabrics which are prepared from fiber or fleece material are also suitable.
Finally, the invention provides for the use of mixed ethers as impregnating agents for the production of wet wipes, in which they can be used in amounts of from 0.01 to 2% by weight, preferably 0.5 to 1% by weight, based on the wipes.
Auxiliaries and Additives
In a further embodiment of the invention, the wet wipes can comprise further customary auxiliaries and additives, in particular complexing agents, such as, for example, citric acid, HEDP or EDTA, which serve both for the stabilization of the ingredients and also for improving the cleaning performance in the case of salt-containing soilings (e.g. water hardness), antibacterial active ingredients such as, for example, hydrogen peroxide and cationic surfactants, preferably ester quats, and skin care agents. Suitable skin care agents are primarily refatting agents, oil components and emulsifiers, as are typically used in cosmetic products.
Oily Bodies
Suitable oily bodies are, for example, Guerbet alcohols based on fatty alcohols having 6 to 18, preferably 8 to 10, carbon atoms, esters of linear C6-C22-fatty acids with linear or branched C6-C22-fatty alcohols or esters of branched C6-C13-carboxylic acids with linear or branched C6-C22-fatty alcohols, such as, for example, myristyl myristate, myristyl palmitate, myristyl stearate, myristyl isostearate, myristyl oleate, myristyl behenate, myristyl erucate, cetyl myristate, cetyl palmitate, cetyl stearate, cetyl isostearate, cetyl oleate, cetyl behenate, cetyl erucate, stearyl myristate, stearyl palmitate, stearyl stearate, stearyl isostearate, stearyl oleate, stearyl behenate, stearyl erucate, isostearyl myristate, isostearyl palmitate, isostearyl stearate, isostearyl isostearate, isostearyl oleate, isostearyl behenate, isostearyl oleate, oleyl myristate, oleyl palmitate, oleyl stearate, oleyl isostearate, oleyl oleate, oleyl behenate, oleyl erucate, behenyl myristate, behenyl palmitate, behenyl stearate, behenyl isostearate, behenyl oleate, behenyl behenate, behenyl erucate, erucyl myristate, erucyl palmitate, erucyl stearate, erucyl isostearate, erucyl oleate, erucyl behenate and erucyl erucate. Also suitable are esters of linear C6-C22-fatty acids with branched alcohols, in particular 2-ethylhexanol, esters of C18-C38-alkylhydroxycarboxylic acids with linear or branched C6-C22-fatty alcohols (cf. DE 19756377 A1), in particular dioctyl malate, esters of linear and/or branched fatty acids with polyhydric alcohols (such as, for example, propylene glycol, dimerdiol or trimertriol) and/or Guerbet alcohols, triglycerides based on C6-C10-fatty acids, liquid mono-/di-/triglyceride mixtures based on C6-C18-fatty acids, esters of C6-C22-fatty alcohols and/or Guerbet alcohols with aromatic carboxylic acids, in particular benzoic acid, esters of C2-C12-dicarboxylic acids with linear or branched alcohols having 1 to 22 carbon atoms or polyols having 2 to 10 carbon atoms and 2 to 6 hydroxyl groups, vegetable oils, branched primary alcohols, substituted cyclohexanes, linear and branched C6-C22-fatty alcohol carbonates such as, for example, dicaprylyl carbonate (Cetiol(copyright) CC), Guerbet carbonates based on fatty alcohols having 6 to 18, preferably 8 to 10, carbon atoms, esters of benzoic acid with linear and/or branched C6-C22-alcohols (e.g. Finsolv(copyright) TN), linear or branched, symmetrical or asymmetrical dialkyl ethers having 6 to 22 carbon atoms per alkyl group, such as, for example, dicaprylyl ether (Cetiol(copyright) OE), ring-opening products of epoxidized fatty acid esters with polyols, silicone oils (cyclomethicones, silicon methicone grades, etc.) and/or aliphatic or naphthenic hydrocarbons such as, for example, squalane, squalene or dialkylcyclohexanes.
Emulsifiers
Suitable emulsifiers are, for example, nonionogenic surfactants from at least one of the following groups:
addition products of from 2 to 30 mol of ethylene oxide and/or 0 to 5 mol of propylene oxide onto linear fatty alcohols having 8 to 22 carbon atoms, onto fatty acids having 12 to 22 carbon atoms, onto alkyl phenols having 8 to 15 carbon atoms in the alkyl group, and alkylamines having 8 to 22 carbon atoms in the alkyl radical;
addition products of from 1 to 15 mol of ethylene oxide onto castor oil and/or hydrogenated castor oil;
addition products of from 15 to 60 mol of ethylene oxide onto castor oil and/or hydrogenated castor oil;
partial esters of glycerol and/or sorbitan with unsaturated, linear or saturated, branched fatty acids having 12 to 22 carbon atoms and/or hydoxycarboxylic acids having 3 to 18 carbon atoms, and adducts thereof with 1 to 30 mol of ethylene oxide;
partial esters of polyglycerol (average degree of self-condensation 2 to 8), polyethylene glycol (molecular weight 400 to 5000), trimethylol-propane, pentaerythritol, sugar alcohols (e.g. sorbitol), alkyl glucosides (e.g. methyl glucoside, butyl glucoside, lauryl glucoside), and polyglucosides (e.g. cellulose) with saturated and/or unsaturated, linear or branched fatty acids having 12 to 22 carbon atoms and/or hydroxycarboxylic acids having 3 to 18 carbon atoms, and adducts thereof with 1 to 30 mol of ethylene oxide;
mixed esters of pentaerythritol, fatty acids, citric acid and fatty alcohol as in German Patent 1165574 and/or mixed esters of fatty acids having 6 to 22 carbon atoms, methyl glucose and polyols, preferably glycerol or polyglycerol.
mono-, di- and trialkyl phosphates, and also mono-, di- and/or tri-PEG alkyl phosphates and salts thereof;
wool wax alcohols;
polysiloxane-polyalkyl-polyether copolymers and corresponding derivatives;
block copolymers, e.g. polyethylene glycol-30 dipolyhydroxystearate;
polymer emulsifiers, e.g. Pemulen grades (TR-1, TR-2) from Goodrich;
polyalkylene glycols and
glycerol carbonate.
The addition products of ethylene oxide and/or propylene oxide onto fatty alcohols, fatty acids, alkyl phenols or onto castor oil are known, commercially available products. These are homolog mixtures whose average degree of alkoxylation corresponds to the ratio of the quantitative amounts of ethylene oxide and/or propylene oxide and substrate with which the addition reaction is carried out. C12/18-fatty acid mono- and diesters of addition products of ethylene oxide onto glycerol are known from German Patent DE 2024051 as refatting agents for cosmetic preparations.
Typical examples of suitable partial glycerides are hydroxystearic acid monoglyceride, hydroxystearic acid diglyceride, isostearic acid monoglyceride, isostearic acid diglyceride, oleic acid monoglyceride, oleic acid diglyceride, ricinoleic acid monoglyceride, ricinoleic acid diglyceride, linoleic acid monoglyceride, linoleic acid diglyceride, linolenic acid monoglyceride, linolenic acid diglyceride, erucic acid monoglyceride, erucic acid diglyceride, tartaric acid monoglyceride, tartaric acid diglyceride, citric acid monoglyceride, citric acid diglyceride, malic acid monoglyceride, malic acid diglyceride and technical-grade mixtures thereof which may also contain small amounts of triglyceride as byproducts from the preparation process. Likewise suitable are addition products of from 1 to 30 mol, preferably 5 to 10 mol, of ethylene oxide onto said partial glycerides.
Suitable sorbitan esters are sorbitan monoisostearate, sorbitan sesquiisostearate, sorbitan diisostearate, sorbitan triisostearate, sorbitan monooleate, sorbitan sesquioleate, sorbitan dioleate, sorbitan trioleate, sorbitan monoerucate, sorbitan sesquierucate, sorbitan dierucate, sorbitan trierucate, sorbitan monoricinoleate, sorbitan sesquiricinoleate, sorbitan diricinoleate, sorbitan triricinoleate, sorbitan monohydroxystearate, sorbitan sesquihydroxystearate, sorbitan dihydroxystearate, sorbitantrihydroxy-stearate, sorbitan monotartrate, sorbitan sesquitartrate, sorbitan ditartrate, sorbitantritartrate, sorbitan monocitrate, sorbitan sesquicitrate, sorbitan dicitrate, sorbitan tricitrate, sorbitan monomaleate, sorbitan sesquimaleate, sorbitan dimaleate, sorbitan trimaleate and technical-grade mixtures thereof. Also suitable are addition products of from 1 to 30 mol, preferably 5 to 10 mol, of ethylene oxide onto said sorbitan esters.
Typical examples of suitable polyglyceryl esters are polyglyceryl-2 dipolyhydroxystearate (Dehymuls(copyright) PGPH), polyglycerol-3 diisostearate (Lameform(copyright) TGI), polyglyceryl-4 isostearate (Isolan(copyright) GI 34), polyglyceryl-3 oleate, diisostearoyl polyglyceryl-3 diisostearate (Isolan(copyright) PDI), polyglyceryl-3 methylglucose distearate (Tego Care(copyright) 450), polyglyceryl-3 beeswax (Cera Bellina(copyright)), polyglyceryl-4 caprate (polyglycerol caprate T2010/90), polyglyceryl-3 cetyl ether (Chimexane(copyright) NL), polyglyceryl-3 distearate (Cremophor(copyright) GS 32) and polyglyceryl polyricinoleate (Admul(copyright) WOL 1403) polyglyceryl dimerate isosteararate, and mixtures thereof. Examples of further suitable polyol esters are the mono-, di- and triesters of trimethylolpropane or pentaerythritol with lauric acid, coconut fatty acid, tallow fatty acid, palmitic acid, stearic acid, oleic acid, behenic acid and the like, which are optionally reacted with 1 to 30 mol of ethylene oxide.
Zwitterionic surfactants can also be used as emulsifiers. Zwittionic surfactants is the term used to describe those surface-active compounds which contain at least one quaternary ammonium group and at least one carboxylate and one sulfonate group in the molecule. Particularly suitable zwitterionic surfactants are the so-called betaines, such as the N-alkyl-N,N-dimethylammonium glycinates, for example cocoalkyl-dimethylammonium glycinate, N-acylaminopropyl-N,N-dimethylammonium glycinates, for example cocoacylamino-propyldimethylammonium glycinate, and 2-alkyl-3-carboxymethyl-3-hydroxyethylimidazoline having in each case 8 to 18 carbon atoms in the alkyl or acyl group, and cocoacylaminoethyl hydroxyethylcarboxymethyl-glycinate. Particular preference is given to the fatty acid amide derivative known under the CTFA name Cocamidopropyl Betaine. Likewise suitable emulsifiers are ampholytic surfactants. Ampholytic surfactants are to be understood as meaning those surface-active compounds which, apart from a C8/18-alkyl- or -acyl group, contain at least one free amino group and at least one xe2x80x94COOH or xe2x80x94SO3H group in the molecule and are capable of forming internal salts. Examples of suitable ampholytic surfactants are N-alkylglycines, N-alkyl-propionic acids, N-alkylaminobutyric acids, N-alkyl-aminodipropionic acids, N-hydroxyethyl-N-alkylamido-propylglycines, N-alkyltaurines, N-alkylsarcosines, 2-alkylaminopropionic acids and alkylaminoacetic acids having in each case about 8 to 18 carbon atoms in the alkyl group. Particularly preferred ampholytic surfactants are N-cocoalkylaminopropionate, cocoacyl-aminoethylaminopropionate and C12/18-acylsarcosine. Finally, suitable emulsifiers are also cationic surfactants which are particularly preferably those of the ester quat type, preferably methyl-quaternized difatty acid triethanolamine ester salts.
These preparations are preferably emulsions, preferably microemulsions or PIT emulsions.